frank-default-large: add MTP draft head (EasiiX Q8_0, draft-mtp+ngram-mod)

Add speculative decoding via EasiiX/Qwen3.8-Flash-Next-MTP-Strix-Halo-GGUF
Q8_0 sidecar (4.1 GB, qwen4exp architecture matching the main model).

- serve-frank-large.sh: SPEC_ARGS array, draft model existence check,
  spec defaults (n_max 4, p_min 0.75, ngl 999, ROCm0)
- frank-default-large.env: MTP tunables section, fix 'no MTP' comment
- kingjones-strix-rocmfp4.md: MTP Draft Head section, spec flags in
  serving profile, EasiiX + PR #27739 citations

Set SPEC_TYPE=none in the env to disable speculative decoding.

scripts/frank-default-large.env

@@ -17,7 +17,8 @@
 # (count=4, low_rank=320), PLE (layer 1, ngram_size=3, heads_per_ngram=8).
 # Q4_0_ROCMFP4_STRIX quant (file_type=105), 113.47 GiB, single GGUF file.
 # PLE table: 50.66 GiB Q8_0, streamed from page cache (never in GPU VRAM).
-# Text-only (no mmproj, no MTP draft head).
+# Text-only (no mmproj).  MTP draft head loaded as a separate GGUF sidecar
+# (EasiiX/Qwen3.8-Flash-Next-MTP-Strix-Halo-GGUF, Q8_0, 4.1 GB).
 #
 # Context: 262144 (256k) x 2 slots.  f16 KV cache (~6.4 GiB per slot,
 # ~12.8 GiB total).  --fit off because the auto-fit code segfaults on this
@@ -82,4 +83,20 @@ REASONING_FORMAT=deepseek
 # Strix Halo unified memory + native gfx1151.
 HSA_OVERRIDE_GFX_VERSION=11.5.1
 
-VERBOSITY=4
+VERBOSITY=4
+
+# MTP draft head (speculative decoding).  The MTP head from
+# Qwen/Qwen3.8-Flash-Next, exported as a standalone Q8_0 GGUF sidecar by
+# EasiiX/Qwen3.8-Flash-Next-MTP-Strix-Halo-GGUF.  Architecture qwen4exp,
+# matching the main model.  Measured +50% decode on code at temp 0 on
+# Strix Halo (gfx1151).  Set SPEC_TYPE=none to disable.
+DRAFT_MODEL_DIR=/home/dank/models/mtp-Qwen3.8-Flash-Next
+DRAFT_MODEL_FILE=mtp-Qwen3.8-Flash-Next-Q8_0.gguf
+SPEC_TYPE=draft-mtp,ngram-mod
+SPEC_DRAFT_N_MAX=4
+SPEC_DRAFT_N_MIN=0
+SPEC_DRAFT_P_MIN=0.75
+SPEC_DRAFT_NGL=999
+SPEC_DRAFT_DEVICE=ROCm0
+SPEC_DRAFT_TYPE_K=f16
+SPEC_DRAFT_TYPE_V=f16